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pollen/pollen/core.rkt

144 lines
6.2 KiB
Racket

#lang racket/base
(require (for-syntax
racket/base
"private/constants.rkt")
racket/match
txexpr/base
xml/path
sugar/define
sugar/coerce
sugar/test
"private/file-utils.rkt"
"setup.rkt"
"cache.rkt"
"pagetree.rkt"
"tag.rkt")
(define is-meta-value? hash?)
(define is-doc-value? txexpr?)
;; if `define-meta` is defined it will pop an error msg if the wrong number of args
;; even though this error will happen after macro expansion, when metas are extracted
;; empty string will merge with surroundings
(provide define-meta)
(define-syntax-rule (define-meta k v kv ...) (begin))
(define+provide current-metas (make-parameter #f))
(define+provide/contract (select* key value-source [caller 'select*])
((coerce/symbol? (or/c is-meta-value? is-doc-value? pagenode? pathish?)) (symbol?) . ->* . (or/c #f txexpr-elements?))
(define metas-result (and (not (is-doc-value? value-source)) (select-from-metas key value-source caller)))
(define doc-result (and (not (is-meta-value? value-source)) (select-from-doc key value-source caller)))
(match (filter values (apply append (map ->list (list metas-result doc-result))))
[(? pair? res) res]
[_ #false]))
(define+provide/contract (select key value-source)
(coerce/symbol? (or/c is-meta-value? is-doc-value? pagenode? pathish?) . -> . (or/c #f txexpr-element?))
(match (select* key value-source 'select)
[(cons res _) res]
[_ #false]))
(module-test-external
(check-equal? (select* 'key '#hash((key . "value"))) '("value"))
(check-equal? (select 'key '#hash((key . "value"))) "value")
(check-false (select* 'absent-key '#hash((key . "value"))))
(check-false (select 'absent-key '#hash((key . "value"))))
(check-equal? (select* 'key '(root (key "value"))) '("value"))
(check-equal? (select 'key '(root (key "value"))) "value")
(check-false (select* 'absent-key '(root (key "value"))))
(check-false (select 'absent-key '(root (key "value"))))
(let ([metas '#hash((key . "value"))])
(check-equal? (select* 'key metas) '("value"))
(check-equal? (select 'key metas) "value")
(check-false (select* 'absent-key metas))
(check-false (select 'absent-key metas)))
(let ([doc '(root (key "value"))])
(check-equal? (select* 'key doc) '("value"))
(check-equal? (select 'key doc) "value")
(check-false (select* 'absent-key doc))
(check-false (select 'absent-key doc))))
(define+provide/contract (select-from-metas key metas-source [caller 'select-from-metas])
;; output contract is a single txexpr-element
;; because metas is a hash, and a hash has only one value for a key.
((coerce/symbol? (or/c is-meta-value? pagenode? pathish?)) (symbol?) . ->* . any/c)
(hash-ref (match metas-source
[(? is-meta-value? ms) ms]
[_ (get-metas metas-source caller)]) key #false))
(module-test-external
(let ([metas '#hash((key . "value"))])
(check-equal? (select-from-metas 'key metas) "value")
(check-false (select-from-metas 'absent-key metas))))
(define+provide/contract (select-from-doc key doc-source [caller 'select-from-doc])
;; output contract is a list of elements
;; because doc is a txexpr, and a txexpr can have multiple values for a key
((coerce/symbol? (or/c is-doc-value? pagenode? pathish?)) (symbol?) . ->* . (or/c #f txexpr-elements?))
(match (se-path*/list (list key) (match doc-source
[(? is-doc-value?) doc-source]
[_ (get-doc doc-source caller)]))
[(? pair? result) result]
[_ #false]))
(module-test-external
(check-equal? (select-from-doc 'key '(root (key "value"))) '("value"))
(check-false (select-from-doc 'absent-key '(root (key "value"))))
(let ([doc '(root (key "value"))])
(check-equal? (select-from-doc 'key doc) '("value"))
(check-false (select-from-doc 'absent-key doc))))
(define (convert+validate-path pagenode-or-path caller)
(define path (if (pagenode? pagenode-or-path)
(build-path (current-project-root) (symbol->string pagenode-or-path))
pagenode-or-path))
(define src-path (or (get-source path) path))
(unless (file-exists? src-path)
(raise-argument-error caller "existing Pollen source, or name of its output path" src-path))
src-path)
(define+provide/contract (get-metas pagenode-or-path [caller 'get-metas])
(((or/c pagenode? pathish?)) (symbol?) . ->* . is-meta-value?)
(cached-metas (convert+validate-path pagenode-or-path caller)))
(define+provide/contract (get-doc pagenode-or-path [caller 'get-doc])
(((or/c pagenode? pathish?)) (symbol?) . ->* . (or/c is-doc-value? string?))
(cached-doc (convert+validate-path pagenode-or-path caller)))
;; This `@` definition is here to provide a hook for the docs.
;; But this is just default tag behavior, and thus would work without the definition.
;; Which is why the splicing tag can be renamed:
;; it just becomes an undefined tag, also with default behavior.
;; For a pollen source, the actual splicing happens when the source is compiled.
;; For a template in the render environment, which is more text-ish,
;; the splicing tag is redefined to produce a basic list.
;; (which is then, by default behavior of `include-template`, merged with the surrounding text)
(define+provide @ (make-default-tag-function '@))
(provide when/splice)
(define-syntax (when/splice stx)
(syntax-case stx ()
[(_ COND . BODY)
(with-syntax ([SPLICING-TAG (datum->syntax stx pollen-splicing-tag)])
#'(if COND
(SPLICING-TAG . BODY)
(SPLICING-TAG)))]))
(provide for/splice for*/splice)
(define-syntax (for/splice/base stx)
(syntax-case stx ()
[(_ ITERATORS . BODY)
(with-syntax ([SPLICING-TAG (datum->syntax stx pollen-splicing-tag)]
[FORM (or (syntax-property stx 'form) #'for/list)])
#'(apply SPLICING-TAG (FORM ITERATORS
(SPLICING-TAG . BODY))))]))
(define-syntax for/splice (make-rename-transformer #'for/splice/base))
(define-syntax (for*/splice stx)
(syntax-case stx ()
[(_ . BODY) (syntax-property #'(for/splice/base . BODY) 'form #'for*/list)]))
(provide when/block) ; bw compat
(define-syntax when/block (make-rename-transformer #'when/splice))